The process of fusion generally consists of mixing an oxidized sample with a lithium borate flux and heating the mix to a temperature of approximately 1000° Celsius. At this temperature the flux melts and dissolves samples to form a perfectly homogenous mass. This homogenous mass is generally subsequently poured either into a preheated platinum mold to produce a glass disk for XRF analysis, or into an unbreakable beaker containing an acid solution to be analysed by atomic absorption (AA), inductively coupled plasma (ICP) or any traditional wet chemistry method.
Heating of the mix occurs in a heat furnace, such as a fluxer, where receptacles such as crucibles are supported by a pivotable supporting assembly having top, bottom, and side supporting members. The supporting assembly maintains a plurality of receptacles in predetermined positions during a rocking of the receptacles provided in the course of the heating process and a rotation leading to the pouring of the homogenous mass into the mold.
Common problems with known support assembly for such apparatuses are that the bottom supporting member often breaks prematurely as a result of creep resulting from the high heat and the flexural stress imposed on the bottom supporting member by the weight of the receptacles and their content, as well as thermal shocks. Another issue is that the heat furnace receptacles tend to move laterally left and right in response to the rocking movement and rotation of the support assembly.
One of the proposed solutions is to provide the bottom supporting member with lateral structures such as bushings, separated by sleeves to provide lateral support to the receptacles. This solution helps with the lateral movement issue; however it requires the assembly of multiple distinct pieces and results in a supporting member having an increased weight. In practice, it has been observed that the flexural stress imposed on the bottom supporting member, in this proposed solution, is such that the flexural stress often causes premature failure and breaking due to the effects of creep.
In view of the above, there is a need for an improved retaining bar and a heat furnace supporting assembly comprising the same which would be able to overcome or at least minimize some of the above discussed prior art concerns.